Added Nano to the list of syntax highlighters (#718)

Also added a reference to `[template variables]` under Gross File Structure, because it's now a top level section.

Author: wxtim

src/dictionaries/proper_nouns

@@ -25,6 +25,7 @@ loadleveler
 lsf
 moab
 Moab
+Nano
 npm
 pbs
 Posix

src/user-guide/writing-workflows/configuration.rst

@@ -104,7 +104,13 @@ Sublime Text 3
 TextMate
    Install the `Cylc.tmbundle`_.
 WebStorm
-      Install the `Cylc.tmbundle`_.
+   Install the `Cylc.tmbundle`_.
+Nano
+   The syntax file can be obtained from the Cylc library by
+   running the following command
+   ``cylc get-resources syntax/cylc.nanorc ~/.config/nano``
+   installation instructions are at the top of the file.
+
 
 Gross File Structure
 ^^^^^^^^^^^^^^^^^^^^
@@ -116,6 +122,9 @@ several top level section headings:
    Information about the workflow e.g. title and description.
 :cylc:conf:`[scheduler]`
    Non task-specific workflow configuration.
+:cylc:conf:`[task parameters]`
+   Parameters for use when defining graphs and tasks.
+   See :ref:`user guide param`.
 :cylc:conf:`[scheduling]`
    Determines when tasks are ready to run.